To establish user equivalence:
1. Create the directories for SSH:
chmod 700 ~/.ssh
2. Generate the user's public and private keys as the oracle user on all nodes in turn. Do not enter a passphrase when prompted, just press 'ENTER' 3 times to accept all defaults.
ssh-keygen -t dsa
ssh-keygen -t rsa
3. Create the authorized_keys file using both public keys for all nodes, copy the file to all nodes, and change the permissions (do this from one node only).
ssh salmon1 cat ~/.ssh/*.pub >> ~/.ssh/authorized_keys
ssh salmon2 cat ~/.ssh/*.pub >> ~/.ssh/authorized_keys
scp ~/.ssh/authorized_keys salmon1:.ssh/authorized_keys
scp ~/.ssh/authorized_keys salmon2:.ssh/authorized_keys
ssh salmon1 'chmod 600 ~/.ssh/authorized_keys'
ssh salmon2 'chmod 600 ~/.ssh/authorized_keys'
4. Visit each node in turn from every node (including itself). This ensure all nodes are added to each node's known_hosts file, and cluster operations can be run from any node in the cluster. This also serves to test the setup to ensure it is working.
[oracle@salmon1]$ ssh salmon1 'hostname ; date'
[oracle@salmon1]$ ssh salmon2 'hostname ; date'
[oracle@salmon2]$ ssh salmon1 'hostname ; date'
[oracle@salmon2]$ ssh salmon2 'hostname ; date'
Each of the above should return the date without prompting for a password.